Objective Measuring the level of disability following trauma is a key step for secondary and tertiary level trauma prevention. It can give important evidence for decision-makers and program implementers on the need for establishing rehabilitation centers. Methods This is a longitudinal follow-up study on 235 road traffic injury survivors. Patients were followed for 12 months, and the outcome was ascertained using the brief WHODAS-II 12-item instrument at 1, 3, 6, and 12-months post-injury. The level of disability was divided into five groups from no disability to very severe based on their disability scores. Work status was assessed at each survey using a single question “are you back to work?” We employed a linear mixed model to identify disability scores changes over time and risk factors associated with disability. Statistically, a significant association was declared at p < 0.05. Results The overall mean disability score was 24.9 ± 11.3 at one month and 8.3 ± 6.4 after 12 months of injury. Disability score has decreased by 1.3 units over time during 12 months post-injury. Functional limitation persisted on 25–88% of participants at specific dimensions of disability at the end of the study. After a year of injury, 44% of participants didn’t return to work. Injury severity score (β = 0.47, p < 0.001, length of hospital stays (β = 0.88, p < 0.005) and discharge against medical advice (β = 2.18, p < 0.001) were found to be predictors of disability following road traffic injuries. Conclusion The current study demonstrated that, though there was a decrease in disability score over time, a significant number of participants were with some degree of limitation after one year of injury, and nearly half of them didn’t return to work. Shortening of long waiting times and counseling services need to be considered by the hospital. Community-based Rehabilitation centers (CBR) should be expanded. Further study should be conducted to uncover the reasons for preferring traditional bone fixers over medical management.